Methods and apparatus for reducing power consumption in optical devices

ABSTRACT

A customer premises device including an optical modem including at least one upstream laser is power controlled to provide one or more reduced power levels of service in response to a detected AC input power failure, and/or in response to control commands, e.g., from an optical line terminal (OLT). The commands control the customer premises device to switch to a reduced power consumption mode of operation. During the reduced power mode one or a few lasers are powered, e.g., on an intermittent but predictable basis. During normal operation mode each of the upstream lasers are powered. One or more receiver circuits are also powered off during reduced power mode operation in some embodiments. A schedule is used in some embodiments to control when one or more upstream lasers and/or receivers are powered. In some embodiments the schedule is determined based on information provided by the OLT.

FIELD

The present invention relates to optical communications systems, andmore particularly, to methods and apparatus for reducing powerconsumption in optical devices including optical modems.

BACKGROUND

Optical communications networks are being increasingly used to offergreater data rates into residential premises. These optical modems havegrown rapidly in deployed numbers from about 2015 and will soon bedeployed in millions per year. A concern from energy saving advocates isthe increased power consumption that these devices consume more power(typically 8 to 18 W) and have no power saving or standby modes comparedwith DOCSIS cable modems (typically 15-18) that do have significantlydeveloped power saving modes (less than 8 W in standby).

The reason for continuously high power operation in optical modems isthe need to have one LASER for each upstream wavelength to be active allof the time. Optical modems may use 1, 2, 4 or in the future morewavelengths, all requiring a separate and continuously powered LASER.

In the case of residential optical modems, power consumption is ofparticular concern in the case of power outages. Residential and/orcommercial premises optical modems are often paired with a relativelysmall backup battery which is intended to supply power in the event of apower outage.

Given the amount of power drawn by the lasers in an optical modem, theamount of time a unit can continue to operate based on battery power isoften in large part a function of the power requirements of the lasersbeing used in the optical modem for uplink communications.

In current systems, all lasers normally remain powered on at the sametime to support uplink communications using multiple differentwavelengths. Continuing to power the full set of lasers can drain abackup battery over time and limit the overall duration the opticalmodem can remain functional during a power outage. While receivecircuitry also tends to draw power, receiver circuits often consume lesspower than the lasers since they simply detect optical signals ratherthan have to generate the light transmissions, e.g., laser light, usedto communicate information.

In view of the above discussion it should be appreciated if methodsand/or apparatus could be developed which could be used to increase thepower efficiency of optical devices and particularly optical modemsincluding two or more lasers.

SUMMARY

Various features relate to methods and apparatus reducing powerconsumption requirements of optical devices, e.g., optical modemsincluding one, two or more than two lasers, e.g., each lasercorresponding to a different frequency of light. In various embodimentsan optical modem supports a full power mode of operation and one or morereduced power modes of operation.

In some embodiments, a single laser is used for upstream communications,and during normal mode the single laser if continuously powered on,while during one or more reduced power modes of operation, the singlelaser is intermittently powered on. In some embodiments, including aplurality of lasers for upstream communications, in the reduced powermode of operation, less than the full set of lasers, e.g., lasers usedto support upstream communication to a network headend, are powered at agiven time with some of the lasers being left unpowered. For furtherpower savings, in some but not necessarily all embodiments some of thedifferent optical receivers and corresponding receiver circuitry ispowered down. Thus depending on the embodiment, a laser used forupstream communication is powered down and in some embodiments thecorresponding downlink circuitry will also be powered down.

While a laser may be, and sometimes is, powered down during at leastsome period of time during power save mode of operation, the methods andapparatus still allow for device availability in at least someembodiments where detection of an off-hook condition of a telephone orother device at a customer premise is detected and trigger powering upof at least one laser and/or resumption of normal mode operation. In onesuch embodiment once an on-hook condition of the device, e.g., phone,which was detected going off hook during power saving mode operation,and thus triggering powering of the laser, is detected as going on hookpower saving mode is resumed and the laser is powered off, e.g., for aperiod of time and/or according to a schedule.

By supporting power saving mode operation, the methods and apparatus ofthe invention allow for use of a backup battery which can be of areasonable size for a residential application while still allowing for24 hour availability for voice calls during power outages and/oremergencies. The methods and apparatus can also be used to facilitatereaching of voluntary small network equipment power consumption targetsand/or government mandated power consumption requirements forresidential device in the event they are implemented or already exist.

Significantly, while an optical network unit implemented in accordancewith the invention may enter a power saving mode of operation, the ONUcan remain registered with a network device such as an OLT in at leastsome embodiments. After an initial registration with an OLT, e.g., afterpower up, the ONU is able to support voice calls. In one such embodimentthe OLT keeps the ONU registered even though it may temporarily cease tocommunicate with the ONU due to ONU power saving mode operation anddepowering of the ONU's laser or lasers and/or optical receivers for aperiod of time. In such embodiments on powering up its laser or lasersand/or optical receiver(s), the ONU can proceed with communicating withthe OLT and proceeding with a voice call without having to re-register.This allows for rapid voice call support even when an ONU switches sfrom power saving to powered operation in response to a device such as aphone going off hook allowing for rapid placement of calls, e.g., inemergencies, since re-registration can be avoided as compared toembodiments where an ONU needs to re-register after ceasingcommunication with an OLT, e.g., due to a laser or receiver beingpowered off.

In some embodiments 2, 3, 4 or more uplink lasers are used and fullypowered during a normal full power mode of operation. Depending on theamount of energy savings and/or data transmission requirements in someembodiments different power saving modes may be supported. For examplewhile landline or wire power is available from the power lines of ahouse but little data is to be transmitted, multiple lasers may remainpowered but with some of the lasers being powered off. For example ifthree lasers are included in a modem and there is little data totransmit one of the lasers may be powered off for a medium power savingmode of operation. In cases where extreme power savings are desired,e.g., because of a power outage and the need to run on battery power orbecause there is an extended period of inactivity in which there is noor little upstream data to be transmitted, the number of lasers andcorresponding receive circuits may be reduced to one laser/receivecircuit pair with the other laser/receiver circuits being powered offand the time in which the lasers and/or transmit/receive circuits in theoptical modem are powered on is controlled by a schedule. Thus in casesof maximum power saving, all the lasers and corresponding opticaltransmit circuits may be, and sometimes are, powered on and off based ona schedule. Information about the schedule on which a customer preemiesdevice will have its lasers and/or circuits powered on and off isexchanged between the customer premises device implementing the powersaving mode of operation and the optical line terminal (OLT) with whichit interacts. In the case where the customer premises device initiatespower saving mode operation, it will communicate schedule information tothe OLT. In the case where a network headend device triggersimplementation of a power save mode of operation due to planned networkmaintenance for some other reason, the OLT will communicate scheduleinformation to the optical modem.

During an implemented power save mode of operation, the optical modemwill power on one or more lasers and/or optical receivers in accordancewith the schedule to be used.

Switching between the full power mode of operation and one or more ofthe reduced power modes of operation can be initiated by the customerpremises device including the modem, e.g., in response to detecting apower outage requiring the device to operate on battery power.Alternatively, a low power mode of operation can be triggered by thecustomer premises device including the optical modem based on a lack ofuser activity and/or data to transmit. When a low power mode ofoperation is initiated by the customer premises device, the customerpremises device communicates information to an upstream device, e.g.,optical line terminal in a network headend such a cable network operatoroffice, indicating that it will be operating in a low power mode ofoperation. In various embodiments the communicated information alsoindicates which lasers/receivers will be in operation and the scheduleon which such operation will be implemented. Based on the receivedinformation the upstream optical terminal with which the optical modeminteracts knows which laser and/or receivers will be powered on and theschedule at which such devices will be powered on. In this way theupstream device will know when it can transmit to the optical modem andon which frequency or frequencies it can communicate.

In the maximum power saving mode of operation power saving is achievedby turning off all but one upstream LASER, referred to as the primarylaser, when traffic is not being sent upstream, the downstream receiverswhich are not in use are also powered down to further save power. Theprimary laser is also powered down most of the time during the maximumpower saving mode of operation based on the schedule, but periodicallypowered back up according to the schedule. The transmit and receivingtime-slots are predetermined based on the schedule which is also knownto the Optical Line Terminal (OLT) in the head-end infrastructure whichwill interact with optical modem based on the schedule. A scheduledpower-down, set by the OLT's scheduler, allows optical modem functionsto be put to sleep for long intervals compared to the required up-timeused to support a ‘keep-alive’ function, enabling power-saving whilemaintaining the ability to be rapidly brought out of standby by eitherby a user of the modem, an application using the modem, or a networkcontroller, e.g., located at the network headend or integrated into theoptical line terminal.

By reducing the power consumption required through the selectiveapplication of power to one or more lasers and/or receive circuits powerconsumption by an optical modem of a customer premises device can bereduced considerably and the amount of time which the device can operateon battery power can be extended considerably beyond the amount of timethat would be possible if all lasers were maintained in a powered stateof operation.

An method of operating a customer premises device including an opticalmodem including at least a first laser, in accordance with someembodiments, comprises: operating in a normal mode of operation in whichthe first laser is continuously powered on for upstream communications;detecting one of: i) a loss in main power availability or ii) a commandto implement a power saving mode of operation; and switching to a firstpower saving mode of operation in response to: i) detecting a command toimplement a power saving mode of operation or ii) detecting a loss ofmain power availability, said first power saving mode of operation beinga mode of operation in which said first laser is powered off for atleast a first period of time. An exemplary customer premises device, inaccordance with some embodiments, comprises: a first laser for upstreamcommunication; a first optical receiver for downstream communication; apower monitoring circuit configured to monitor main power availability;and a processor configured to: operate the customer premises device in anormal mode of operation in which the first laser is continuouslypowered on for upstream communications; detect one of: i) a loss in mainpower availability or ii) a command to implement a power saving mode ofoperation; and switch to a first power saving mode of operation inresponse to: i) detecting a command to implement a power saving mode ofoperation or ii) detecting a loss of main power availability, said firstpower saving mode of operation being a mode of operation in which saidfirst laser is powered off for at least a first period of time.

While various features discussed in the summary are used in someembodiments it should be appreciated that not all features are requiredor necessary for all embodiments and the mention of features in thesummary should in no way be interpreted as implying that the feature isnecessary or critical for all embodiments. Numerous additional featuresand embodiments are discussed in the detailed description which follows.Numerous additional benefits will be discussed in the detaileddescription which follows.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a drawing of an exemplary communications system including anoptical line terminal (OLT) located at a network headend which iscoupled to a plurality of customer premises which each include customerpremises device that includes an optical modem and a processor.

FIG. 2 shows an exemplary customer premises device implemented inaccordance with the invention that includes an optical modem thatsupports a normal mode operation and one or more power saving modes ofoperation.

FIG. 3 shows an exemplary normal schedule used for a normal mode ofoperation in which all of the lasers and receiver circuits in theoptical modem are powered on during the full set of time slots in theschedule.

FIG. 4 shows a first reduced power schedule associated with a firstreduced power mode of operation in which one laser/optical receiver pairis kept in a powered on state and various other lasers/receivers arepowered on/off according to the schedule.

FIG. 5 shows a second schedule used to support a maximum power savingmode of operation in which a single laser and optical receiver arepowered on for brief periods of time according to the schedule, withother lasers and optical receivers being powered off.

FIG. 6A is a first part of flowchart of an exemplary method of operatinga customer premises device including an optical modem including aplurality of lasers in accordance with an exemplary embodiment.

FIG. 6B is a second part of flowchart of an exemplary method ofoperating a customer premises device including an optical modemincluding a plurality of lasers in accordance with an exemplaryembodiment.

FIG. 6 comprises the combination of FIG. 6A and FIG. 6B.

FIG. 7A is a drawing of a first part of an exemplary assembly ofcomponents which may be included in a customer premises device, e.g., adevice including an optical modem including a plurality of upstreamlasers, in accordance with an exemplary embodiment.

FIG. 7B is a drawing of a second part of an exemplary assembly ofcomponents which may be included in a customer premises device, e.g., adevice including an optical modem including a plurality of upstreamlasers, in accordance with an exemplary embodiment.

FIG. 7 comprises the combination of FIG. 7A and FIG. 7B.

FIG. 8A is a first part of a flowchart of an exemplary method ofoperating a customer premises device including an optical modemincluding at least a first laser used for upstream communications inaccordance with an exemplary embodiment.

FIG. 8B is a second part of a flowchart of an exemplary method ofoperating a customer premises device including an optical modemincluding at least a first laser used for upstream communications inaccordance with an exemplary embodiment.

FIG. 8C is a third part of a flowchart of an exemplary method ofoperating a customer premises device including an optical modemincluding at least a first laser used for upstream communications inaccordance with an exemplary embodiment.

FIG. 8, comprising the combination of FIG. 8A, FIG. 8B and FIG. 8C.

FIG. 9A is a drawing of a first part of an exemplary assembly ofcomponents which may be included in a customer premises device, e.g., adevice including an optical modem including at least one of upstreamlaser, in accordance with an exemplary embodiment.

FIG. 9B is a drawing of a second part of an exemplary assembly ofcomponents which may be included in a customer premises device, e.g., adevice including an optical modem including at least one upstream laser,in accordance with an exemplary embodiment.

FIG. 9 comprises the combination of FIG. 9A and FIG. 9B.

DETAILED DESCRIPTION

FIG. 1 is a drawing of an exemplary communications system 100 includingan optical line terminal (OLT) 102 located in a network headend 103, aplurality of optical network units (ONUs) (ONU 1 104, ONU 2 106, . . . ,ONU M 108), each ONU located at a different customer premises (customerpremises 1 105, customer premises 2 107, . . . , customer premises M109), respectively, and an optical coupler 112, e.g., an opticalsplitter/combiner, coupled together as shown. Sometimes, the ONUs (104,106, . . . , 108) are referred to as optical modems. In someembodiments, the ONUs (104, 106, . . . , 108) are each included as partof an optical modem. Optical fiber cable 110 couples the network headendOLT 102 to optical coupler 112. Optical fiber cable 114 couples ONU 1104 to optical coupler 112. Optical fiber cable 116 couples ONU 2 106 tooptical coupler 112. Optical fiber cable 118 couples ONU 3 108 tooptical coupler 112. While the OLT is described as being positioned atthe network headend it should be appreciated that the OLT may be, andsometimes is, located at another position external to a customerpremises, e.g., at a location outside the customer premises at alocation between the customer premises and the connection to the networkheadend. Thus is should be appreciated that depending on the embodimentthe OLT can be located in a Headend and/or in an hardened cabinetlocated closer to the customer base with a large system including OLTsat various locations depending on the particular implementation. RemoteOLT's (R-OLTS) which are small OLTs can reside in a node enclosure.These R-OLT's can be installed on the Hybrid Fiber-Coaxial (HFC) planteither on the strand or for underground plant located within cablevaults or “dog houses”. Thus it should be appreciated that OLTs can bepresent at various locations in a system outside a customer premisewhere the ONU with which an OLT interacts is located.

Optical line terminal (OLT) 102 includes a processor 120, e.g., a CPU,optical interfaces (I/Fs) 122, a network communications interface 124,and memory 126, coupled together via a bus 128 over which the variouselements may interchange data and information. Optical interfaces 122includes a plurality of optical interfaces corresponding to differentcustomer premises (optical interface 1 130, corresponding to customerpremises (CP) 1 103 and ONU 1 104, optical interface 2 132,corresponding to CP 2 105 and ONU 2 106, . . . , optical interface M134, corresponding to CP M 107 and ONU M 109.

Optical interface 1 130 of OLT 102 includes four optical receiver(OR)/optical transmitter (OT) pairs ((OR1 131, OT1 133), (OR2 137, OT2139), (OR3 143, OT3 145), (OR4 149, OT4 121). Each of the opticaltransmitters (OT1 133, OT2 139, OT3 145, OT4 121) of optical interface130 of OLT 102 includes a downstream, e.g. downlink, laser (DL1 135, DL2141, DL3 147, DL4 123), respectively. OR1 131 of OLT 102 receivesoptical signals from OT1 162 of ONU 1 104. OT1 133 of OLT 102 transmitsoptical signals to OR1 164 of ONU 1 104. OR2 137 of OLT 102 receivesoptical signals from OT2 165 of ONU 1 104. OT2 139 of OLT 102 transmitsoptical signals to OR2 167 of ONU 1 104. OR3 143 of OLT 102 receivesoptical signals from OT3 168 of ONU 1 104. OT3 145 of OLT 102 transmitsoptical signals to OR3 170 of ONU 1 104. OR4 149 of OLT 102 receivesoptical signals from OT4 171 of ONU 1 104. OT4 121 of OLT 102 transmitsoptical signals to OR4 173 of ONU 1 104.

Network communications interface 124 includes receiver RX1 136 andtransmitter TX 1 238. Network communications interface 124 couples theOLT 102 to other network nodes, e.g. in the headend, to other networksand/or the Internet. OLT 102 transmits signals including messages, e.g.,control messages and/or user data messages, to other network nodesand/or to other devices, e.g., end node devices.

Memory 126 includes an assembly of components 140, e.g., an assembly ofsoftware components, e.g. software routines and/or software modules, anddata/information 142. Data information 142 includes schedules 144 andONU status information (ONU 1 status information 146, . . . , ONU Mstatus information 148).

Optical network unit 1 (ONU 1 104) includes an optical interface 1 152.In some embodiments the ONU includes a single optical transmitter(OT(/receiver (OR) pair. However the number of OT/OR pairs can varydepending on the particular embodiment. In the FIG. 1 example forpurposes of explaining the invention, an ONU 104 with four opticaltransmitter (OT)/optical receiver (OR) pairs ((OT1 162, OR1 164), (OT2165, OR2 167), (OT3 168, OR3 170), (OT4 171, OR4 173) is shown. However,it should be appreciated that in other embodiments a ONU with a singleOT/OR pair is used. In embodiments with a single OT/OR pair, the singleOT and/or OR pair are powered on and/or based on the particular mode ofoperation being used with the OT/OR pair normally being powered onduring normal mode operation but with the PT and/or OR beingintermittently powered when operation in a power saving mode ofoperation.

In more advanced embodiments the number of OT/OR pairs powered at agiven time may, and sometimes does, vary based on the mode of operationand/or a schedule used to control the supply of power to the devices inthe ONU.

Each of the optical transmitters (OT1 162, OT2 165, OT3 168, OT4 171) ofONU 1 104 includes a upstream, e.g., uplink, laser (UL1 153, UL2 166,UL3 169, UL4 172), respectively. Sometimes upstream lasers are referredto as uplink lasers. In some embodiments, the optical transmitter andoptical receivers are part of optical interface 152.

Optical network unit (ONU) 1 104 further includes a plurality ofprocessors (processor 1 150, . . . , processor N1 151), e.g., aplurality of CPUs, an optical interface 152, a plurality of processingcircuitry (processing circuitry 1 154, . . . , processing circuitry N1155), memory 156 including schedules 174, an A/C power supply 157 (mainpower source), a battery 158 (back-up power source), a power supply 159,which generates a plurality of DC voltages (VDC1, VDCN3) used internallyby the ONU 1 104 and a plurality of AC voltages (VAC1, VACN4) usedinternally by the ONU 1 104. While the ONU includes a battery backup inthe exemplary illustrated embodiment which is shown as part of the ONU,it should be appreciated that in some embodiments the battery backuppower source is external to the ONU. The processor of the ONU and thebattery back up source, whether internal or external, has acommunication channel with the processor of the ONU allowing theprocessor of the ONU to determine the overall health of the battery andif the battery has lost commercial, e.g., external line power.

ONU 1 104 further includes a battery monitoring circuit 161, and controlcircuitry 161 for controlling, e.g., under the direction of processor 1150, power on/off state for various individual components includedwithin ONU 1 104, including, e.g., upstream lasers, optical receivers,optical transmitters, processors, e.g., processor 2, . . . , processorN1 152, and processing circuitry (154, . . . 155). CPE ONU 1 104 furtherincludes electrical I/O communications interfaces 153 for communication,e.g., via wired or wireless signals, with other devices or components atthe customer premises, e.g., end node devices. ONU 1 104 furtherincludes an analog telephone adaptor (ATA) 199, which can be, andsometime is, coupled to telephone, fax maschine, or other device,located at the customer premises.

FIG. 2 shows an exemplary customer premises device 200 implemented inaccordance with the invention that includes an optical modem thatsupports a normal mode operation and one or more power saving modes ofoperation. Customer premises device 200 is a customer premises equipment(CPE) optical network unit (ONU), e.g., an optical modem. Customerpremises device 200 is, e.g., any of the ONUs (104, 106, . . . , 108) ofsystem 100 of FIG. 1.

Customer premises device 200 includes fiber optic cable coupler(s) 236coupled, e.g., connected, to optical interface 206. Optical interface206 couples each of the optical transmitter/receiver pairs in customerpremises device 200 to a fiber connected to one of the optical fibercouplers in coupler(s) 236. In some embodiments, the optical transmitterand optical receivers are considered to be part of the optical interface206.

Customer premises device 200 includes four optical transmitter(OT)/optical receiver (OR) pairs ((OT1 218, OR1 220), (OT2 222, OR2224), (OT3 226, OR3 2277), (OT4 230, OR4 231). Each of the opticaltransmitters (OT1 218, OT2 222, OT3 226, OT4 230) of customer premisesdevice 200 includes an upstream, e.g., uplink, laser (UL1 219 usingfrequency F1, UL2 223 using frequency F2, UL3 227 using frequency F3,UL4 231 using frequency F4), respectively. In some embodiments, opticalcoupler(s) 236 includes a single optical coupler coupling the 4 opticalTX/RX pairs onto a single optical fiber. In other embodiments, opticalcoupler(s) 236 includes a plurality of optical couplers, e.g. one foreach optical TX/RX pair included in device 200, with each couplercorresponding to a different optical fiber. In some embodiments, thenumber of optical couplers used and number of optical fibers aredetermined based on the different frequencies used by the optical TX/RXpairs and the characteristics of the fiber(s) being used.

Customer premises device 200 further includes a plurality of processors(processor 1 202, . . . , processor N1 204), electrical I/Ocommunications interfaces 208, a plurality of processing circuits(processing circuitry 1 210, . . . , processing circuitry 212), anassembly of hardware circuits 214, e.g., assembly of circuits, memory216, and analog telephone adaptor (ATA) 299, coupled together andcoupled to the electrical interfaces of optical transmitters (218, 222,226, 228) and to the electrical interfaces of optical receivers (110,224, 228, 232) via bus 234, over which the various elements mayinterchange data and information.

Customer premises device 200 further includes an AC power supply (mainpower sources 238, a power supply 242, a battery 244 (back-up powersource), an input power fail detection and status circuit 246, a batterymonitoring circuit 248, and a power control circuit 249. AC power supply238 receives 120 VAC In power 240, and outputs filtered power to powersupply 242, via power cable 277. The battery 244 is coupled to powersupply via power cable 279, providing the power supply 242 with a backupsource of input power, e.g., to be used if AC power fails or isunacceptable. Power supply 242 generates a plurality of DC voltages(VDC1 273, . . . , VDCN3 274) to be used internally by variouscomponents of device 200. Power supply 242 also generates a plurality ofAC voltages (VAC1 275, VACN4 276) to be used internally by variouscomponents of device 200. Input power fail detection and status circuit278, which coupled to AC power source via link 278, monitors the inputAC power to detect power status, e.g., present and acceptable, notpresent, out-of-spec, etc., and reports current status to the processor202 via link 247. Battery monitoring circuit 248, which is coupled tobattery 244 via sense leads 280, monitors the battery 248 to determineits status, e.g. current voltage and estimated remaining stored energyin the battery 244. Battery monitoring circuit 248 is coupled toprocessor 202 via link 281 and reports battery status information to theprocessor 202.

Power control circuit 249, under the control of processor 249 generatesand sends power on/off control signals, e.g., to each of a plurality ofindividual components with customer premise device 200. Power on/offcontrol signals (COT1 258, COT2 259, COT3 260, COT4 261) are used tocontrol power to optical transmitters (218, 222, 226, 230),respectively. Power on/off control signals (CUL1 262, CUL2 263, CUL3264, CUL4 265) are used to control power to upstream lasers (219, 223,227, 231), respectively. Power on/off control signals (COR1 266, COR2267, COR3 268, COR4 269) are used to control power to optical receivers(220, 224, 228, 232), respectively. Power on/off control signals (CPC1270, . . . , CPCN2 271) are used to control power to processingcircuitry (210, . . . , 212), respectively. Power on/off control signalCPN1 272 is used to control power to processor N1 204.

Electrical I/O communications interfaces 208 includes a wired interface250 and a wireless interface 251. Wired interface 250 includes receiver252 and transmitter 253. Wireless interface 251, e.g. a WiFi interface,includes wireless receiver 254 coupled to receive antenna 256 andwireless transmitter 255 coupled to transmit antenna 257. In someembodiments, the same antenna or same set of antennas is used for bothtransmit and receive.

Memory 216 includes assembly of components 258, e.g., an assembly ofsoftware components, e.g., routines, and data/information 259.Data/information 259 includes schedules 260, power status information261, and mode information 262.

FIG. 3 shows an exemplary normal schedule 300 used for a normal mode ofoperation in which all of the lasers and receiver circuits in theoptical modem are powered on during the full set of time slots in theschedule. First Column 302 identifies the component which is being powercontrolled to be on or off during different times in the schedule.Second column 304 shows on/off status for time interval T1. Third column306 shows on/off status for time interval T2. Fourth column 308 showson/off status for time interval T3. Fifth column 310 shows on/off statusfor time interval T4. Sixth column 312 shows on/off status for timeinterval T5.

First row 314 and second row 316 include column header identificationinformation. Third row 318 includes information identifying theupstream, e.g., uplink, laser 1 (UL 1) is ON during each of the timeslots (T1, T2, T3, T4, T5) during normal operation. Fourth row 320includes information indication that optical receiver 1 (OR1) is ONduring each of the time slots (T1, T2, T3, T4, T5) during normaloperation. Fifth row 322 includes information identifying the upstream,e.g., uplink, laser 2 (UL 2) is ON during each of the time slots (T1,T2, T3, T4, T5) during normal operation. Sixth row 324 includesinformation indication that optical receiver 2 (OR2) is ON during eachof the time slots (T1, T2, T3, T4, T5) during normal operation. Seventhrow 326 includes information identifying the upstream, e.g., uplink,laser 3 (UL 3) is ON during each of the time slots (T1, T2, T3, T4, T5)during normal operation. Eighth row 328 includes information indicationthat optical receiver 3 (OR3) is ON during each of the time slots (T1,T2, T3, T4, T5) during normal operation. Ninth row 330 includesinformation identifying the upstream, e.g., uplink, laser 4 (UL 4) is ONduring each of the time slots (T1, T2, T3, T4, T5) during normaloperation. Tenth row 332 includes information indication that opticalreceiver 4 (OR4) is ON during each of the time slots (T1, T2, T3, T4,T5) during normal operation.

FIG. 4 shows a first reduced power schedule 400 associated with a firstreduced power mode of operation in which one laser/optical receiver pairis kept in a powered on state and various other lasers/receivers arepowered on/off according to the schedule. First reduced power schedule400 is also referred to as intermediate power saving schedule. FirstColumn 402 identifies the component which is being power controlled tobe on or off during different times in the schedule. Second column 404shows on/off status for time interval T1. Third column 406 shows on/offstatus for time interval T2. Fourth column 408 shows on/off status fortime interval T3. Fifth column 410 shows on/off status for time intervalT4. Sixth column 412 shows on/off status for time interval T5.

First row 414 and second row 416 include column header identificationinformation. Third row 418 includes information identifying theupstream, e.g., uplink, laser 1 (UL 1) is ON during each of the timeslots (T1, T2, T3, T4, T5, . . . ) during first reduced power operation.Fourth row 420 includes information indication that optical receiver 1(OR1) is ON during each of the time slots (T1, T2, T3, T4, T5, . . . )during first reduced power operation. Fifth row 422 includes informationidentifying the upstream, e.g., uplink, laser 2 (UL 2) is (ON, OFF, ON,OFF, ON, . . . ) during slots (T1, T2, T3, T4, T5, . . . ),respectively, during first reduced power operations. Sixth row 324includes information indication that optical receiver 2 (OR2) is (ON,OFF, ON, OFF, ON, . . . ) during slots (T1, T2, T3, T4, T5, . . . ),respectively, during first reduced power savings. Seventh row 326includes information identifying the upstream, e.g., uplink, laser 3 (UL3) is OFF during each of the time slots (T1, T2, T3, T4, T5, . . . )during first reduced power operation. Eighth row 328 includesinformation indication that optical receiver 3 (OR3) is OFF during eachof the time slots (T1, T2, T3, T4, T5, . . . ) during first reducedpower operation. Ninth row 330 includes information identifying theupstream, e.g., uplink, laser 4 (UL 4) is OFF during each of the timeslots (T1, T2, T3, T4, T5, . . . ) during first reduced power operation.Tenth row 332 includes information indication that optical receiver 4(OR4) is OFF during each of the time slots (T1, T2, T3, T4, T5, . . . )during first reduced power operation.

FIG. 5 shows a second schedule 500 used to support a maximum powersaving mode of operation in which a single laser and optical receiverare powered on for brief periods of time according to the schedule, withother lasers and optical receivers being powered off. First Column 502identifies the component which is being power controlled to be on or offduring different times in the schedule. Second column 504 shows on/offstatus for time interval T1. Third column 506 shows on/off status fortime interval T2. Fourth column 508 shows on/off status for timeinterval T3. Fifth column 510 shows on/off status for time interval T4.Sixth column 512 shows on/off status for time interval T5. Seventhcolumn 513 shows on/off status for time interval T6.

First row 514 and second row 516 include column header identificationinformation. Third row 518 includes information identifying theupstream, e.g., uplink, laser 1 (UL 1) is (OFF, OFF, ON, OFF, OFF, ON)during each of the time slots (T1, T2, T3, T4, T5, T6, . . . ) duringmaximum power saving operation. Fourth row 520 includes informationindication that optical receiver 1 (OR1) is (OFF, OFF, ON, OFF, OFF, ON)during each of the time slots (T1, T2, T3, T4, T5, T6, . . . ) duringmaximum power saving operation. Fifth row 522 includes informationidentifying the upstream, e.g., uplink, laser 2 (UL 2) is OFF duringeach of the time slots (T1, T2, T3, T4, T5, T6, . . . ) during maximumpower savings operation. Sixth row 524 includes information indicationthat optical receiver 2 (OR2) is OFF during each of the time slots (T1,T2, T3, T4, T5, T6, . . . ) during maximum power savings operation.Seventh row 526 includes information identifying the upstream, e.g.,uplink, laser 3 (UL 3) is OFF during each of the time slots (T1, T2, T3,T4, T5, T6, . . . ) during maximum power savings operation. Eighth row528 includes information indication that optical receiver 3 (OR3) is OFFduring each of the time slots (T1, T2, T3, T4, T5, T6, . . . ) duringmaximum power savings operation. Ninth row 530 includes informationidentifying the upstream, e.g., uplink, laser 4 (UL 4) is OFF duringeach of the time slots (T1, T2, T3, T4, T5, T6, . . . ) during maximumpower savings operation. Tenth row 532 includes information indicationthat optical receiver 4 (OR4) is OFF during each of the time slots (T1,T2, T3, T4, T5, T6, . . . ) during maximum power savings operation.

FIG. 6, comprising the combination of FIG. 6A and FIG. 6B, is aflowchart 600 of an exemplary method of operating a customer premisesdevice including an optical modem including a plurality of lasers inaccordance with an exemplary embodiment. In some embodiments thecustomer premises device implementing the flowchart 600 is an opticalnetwork unit (ONU), e.g., one of ONUs (104, 106, . . . , 108) of FIG. 1or ONU 200 of FIG. 2 or a customer premises device including an ONU,implemented in accordance with an exemplary embodiment. Operation startsin step 602 in which the customer premises device including an opticalmodem including a plurality of lasers is powered on and initialized.Operation proceeds from start step 602 to step 604.

In step 604 the customer premises device is operated in a normal mode ofoperation in which multiple lasers used for upstream communications arepowered on. In some embodiments, step 604 includes one or both of steps606 and 608. In step 606 the customer premises device powers a first setof lasers, e.g. all of the lasers, used for upstream communications,during said normal mode of operation. In step 608 the customer premisesdevices powers on and uses all downstream optical receivers during saidnormal mode of operation. Operation proceeds from step 604 to step 610.

In step 610 the customer premises device monitors for a change in mainpower availability and for a command to implement a mode of operation,said mode of operation being one of said normal mode of operation and apower saving mode of operation. Step 610 may, and sometimes does,include step 612, in which the customer premises device detects one of achain in main power availability or a command to implement a mode ofoperation, said mode of operation being one of a normal mode ofoperation and a power saving mode of operation. Step 612 includes step614, 616, 618 and 620; one of steps 614, 616, 618 and 620 is performedduring each iteration of step 612. In step 614 the customer premisesdevice detects a command to implement a power saving mode of operation.In step 616 the customer premises device detects a loss of main poweravailability. In step 618 the customer premises device detects a commandto implement a normal mode of operation. In step 620 the customerpremises device detects restoration of main power availability.

Operation proceeds from step 614 or step 616 to step 622. In step 622the customer premises device switches to a first power saving mode ofoperation, e.g., a maximum power saving mode of operation in which atmost one upstream laser is operated at a given point in time, inresponse to: i) detecting a command to implement a power saving mode ofoperation or ii) detecting a loss of main power availability. Step 622includes step 624 in which the customer premises device turns off powerto one or more lasers. Operation proceeds from step 622 to step 625 andstep 626.

In step 625 the customer premises device operates in the power savingmode of operation. Step 625 includes step 627, in which the customerpremises device supplies power to a single laser used for upstreamcommunication and keeps one or more additional lasers used for upstreamcommunications powered off (during at least some time period) duringsaid first power saving mode of operation.

In step 626 if the switching to the first power saving mode of operationis in response to detecting a loss of main power availability, thenoperation proceeds from step 626 to step 628; otherwise, operationproceeds from step 626, via connecting node A 630 to step 632.

Returning to step 628, in step 628 the customer premises devicecommunicates to an optical line terminal (OLT) that the customerpremises device is switching to the first power saving mode ofoperation. Operation proceeds from step 628, via connecting node A 630to step 632.

In step 632, the customer premises device receives from the OLTscheduling information indicating an amount of time (e.g., a value usedin a count down timer or more advance scheduling information that can beused to determine a laser and/or receiver power on and off schedule) thecustomer premises device should maintain its laser used for upstreamdata communication in a powered off state prior to powering one at leastone laser as part of operating in said first power saving mode ofoperation. Operation proceeds from step 632 to step 634.

In step 634 the customer premises device places the lasers used forupstream communications in the powered off state. Operation proceedsfrom step 634 to step 636. In step 636 the customer premises devicedetermines when said amount of time the customer premises device shouldmaintain its lasers, used for upstream data communications, in a poweredoff state should be reached, e.g., the customer premises devicesdetermines when the countdown time will expire. Operation proceeds fromstep 636 to step 638

In step 638 the customer premises device determines if the amount oftime the customer premises device is to maintain its lasers, used forupstream data communications, in the power off state has been reached,e.g., determines if the counter timer has expired, and control operationas a function of the determination. If the determination of step 638, isthat the amount of time has not been reached, then operation proceedsfrom step 638 to step 640; otherwise, operation proceeds from step 638to step 642. In addition, in some embodiments the ONU monitors for an“off hook” signal from an analog telephone adaptor (ATA) coupled to orincluded in the ONU. If an off-hook condition is detected while the ONUis operating in power save mode it will trigger the lasers and opticalreceiver in the ONU to be powered on. Similarly if a transition from anoff-hook to on-hook ATA transition is detected, in some embodiments thistriggers a transition to power saving mode operation from normal modeoperation in some embodiments, e.g., with the timer used to control thepower off time of the laser and/or schedule being restarted.

In step 640, the customer premises device maintains the lasers, used forupstream data communication, in a powered off state. Operation proceedsfrom step 640 to the input of step 638 for another check at a laterpoint in time.

Returning to step 642, in step 642 the customer premises devicedetermines that said amount of time the customer premises device shouldmaintain its lasers, used for upstream data communication, in thepowered off state has been reached. Operation proceeds from step 642 tostep 644.

In step 644 the customer premises device powers up a first laser, e.g.,a primary laser, used for upstream communication, in response todetermining that the amount of time has been reached. Operation proceedsfrom step 644 to step 646.

In step 646 the customer premises device sends a message to the OLTindicating that the customer premises device is active, e.g., cantransmit and receive data via the optical interface including the firstlaser. Operation proceeds from step 646 to step 648.

By having had the ONU inform the OLT that is was going into power savemode, e.g., due to loss of line power relying on battery back power, theONU informs the OLT that despite the laser temporally being powered offand a temporary interruption of communication with the OLT, the OLTshould continue to consider the ONU a valid registered device. In thisway the OLT is made aware that is should allow the ONU to remainregistered with the OLT and skip the normal registration process thatwould normally be required when an ONU is powered on and beginscommunicating with the OLT. This allows for what can be considered afast registration process with ONU simply singling that it is once againactive and powered on without requiring the ONU to proceed with acomplete new registration process after powering up its laser. This isimportant so a 911 call can be made with little or no delay from thecustomer premise where the ONU switched to power save mode operation.

In step 648 the customer premises device exchanges at least some datawith the OLT, e.g., during a power on time interval. In variousembodiments, step 648 includes one or more or all of steps 650, 652 and654. Steps 650 and 652 may be performed multiple times. In step 650 thecustomer premises device transmits data to the OLT using the firstlaser. In step 652 the customer premises device receives data from theOLT using a first optical receiver. In step 654 the customer premisesdevice determines that the end of the power on time interval has beenreached. Operation proceeds from step 654 or step 648 to step 634(another iteration), in which the customer premises device places thelasers used for upstream communications in the powered off state. Atthis point, the countdown timer or equivalent mechanism for determiningoff time is re-initialized and countdown restarted.

Returning to step 612, step 612 includes step 618 in which the customerpremises device detects a command to implement a normal mode ofoperation and step 620 in which the customer premises device detectsrestoration of main power availability. Operation proceeds from step 618or step 620 to step 623. In step 623 the customer premises device powersthe lasers in the first set of lasers, used for upstream communications,in response to detecting a change in main power availability indicatingthat main power is available or a command to implement the normal modeof operation.

FIG. 7, comprising the combination of FIG. 7A and FIG. 7B, is a drawingof an exemplary assembly of components 700, comprising Part A 701 andPart B 703, which may be included in a customer premises (CP) device,e.g., a CP device including an optical modem including a plurality oflasers, e.g., an optical network unit (ONU), in accordance with anexemplary embodiment. Exemplary assembly of components 700 is, e.g.included in customer premises device 200 of FIG. 2, e.g., a ONU, in anyof the customer premises devices (ONU 1 104, ONU 2 106, . . . ONU M 108)of FIG. 1, and/or in an customer premises device, e.g., customerpremises device including an optical modem (such as an ONU) including aplurality of lasers for upstream communications, implementing the methodof flowchart 600 of FIG. 6, implemented in accordance with an exemplaryembodiment.

The components in the assembly of components 700 can, and in someembodiments are, implemented fully in hardware within a processor, e.g.,processor 202, e.g., as individual circuits. The components in theassembly of components 700 can, and in some embodiments are, implementedfully in hardware within the assembly of hardware components 214, e.g.,as individual circuits corresponding to the different components. Inother embodiments some of the components are implemented, e.g., ascircuits, within processor 202 with other components being implemented,e.g., as circuits within assembly of components 214, external to andcoupled to the processor 202. As should be appreciated the level ofintegration of components on the processor and/or with some componentsbeing external to the processor may be one of design choice.Alternatively, rather than being implemented as circuits, all or some ofthe components may be implemented in software and stored in the memory216 of the customer premises device 200, with the components controllingoperation of customer premises device 200 to implement the functionscorresponding to the components when the components are executed by aprocessor e.g., processor 202. In some such embodiments, the assembly ofcomponents 700 is included in the memory 216 as part of assembly ofsoftware components 258. In still other embodiments, various componentsin assembly of components 700 are implemented as a combination ofhardware and software, e.g., with another circuit external to theprocessor providing input to the processor which then under softwarecontrol operates to perform a portion of a component's function.

When implemented in software the components include code, which whenexecuted by a processor, e.g., processor 202, configure the processor toimplement the function corresponding to the component. In embodimentswhere the assembly of components 700 is stored in the memory 216, thememory 215 is a computer program product comprising a computer readablemedium comprising code, e.g., individual code for each component, forcausing at least one computer, e.g., processor 202, to implement thefunctions to which the components correspond.

Completely hardware based or completely software based components may beused. However, it should be appreciated that any combination of softwareand hardware, e.g., circuit implemented components may be used toimplement the functions. As should be appreciated, the componentsillustrated in FIG. 7 control and/or configure the customer premisesdevice 200 or elements therein such as the processor 202, to perform thefunctions of corresponding steps illustrated and/or described in themethod of one or more of the flowcharts, signaling diagrams and/ordescribed with respect to any of the Figures. Thus the assembly ofcomponents 700 includes various components that perform functions ofcorresponding one or more described and/or illustrated steps of anexemplary method.

Assembly of components 700 includes a component 704 configured tooperate the customer premises device in a normal mode of operation inwhich multiple lasers used for upstream communications are powered on.In various embodiments, component 704 includes one or both of acomponent 706 configured to power a first set of lasers, e.g., all ofthe lasers, used for upstream communication, during said normal mode ofoperation, and a component 708 configured to power on and use alldownstream optical receivers during said normal mode of operation.

Assembly of components 700 further includes a component 710 configuredto operate the customer premises device to monitor for a change in mainpower availability and for a command to implement a mode of operation,said mode of operation being one of said normal mode of operation and apower saving mode of operation. Component 710 includes a component 712configured to detect one of a change in main power availability or acommand to implement a mode of operation, said mode of operation beingsaid normal mode of operation and said power saving mode of operation.Component 712 includes a component 714 configured to detect a command toimplement a power saving mode of operation, a component 716 configuredto detect a loss of main power availability, a component 718 configuredto detect a command to implement normal mode of operation, and acomponent 720 configured to detect restoration of main poweravailability.

Assembly of components 700 further includes a component 722 configuredto operate the customer premises device to switch to a first powersaving mode of operation (e.g., a maximum power saving mode of operationin which at most one upstream laser is operated at a given point intime) in response to: i) detecting a command to implement a power savingmode of operation or ii) detecting a loss of main power availability,e.g., in response to component 714 detecting a command to implement apower saving mode of operation or component 716 detecting a loss of mainpower availability. Component 722 includes a component 724 configured toturn off power to one or more lasers.

Assembly of components 700 further includes a component 723 configuredto power the lasers in the first set of laser, used for upstreamcommunications, in response to detecting, e.g., by component 720, achange in main power availability indicating that main power isavailable or in response to detecting, e.g. by component 718, a commandto implement the normal mode of operation.

Assembly of components 700 further includes a component 725 configuredto operate the customer premises device in the first power saving modeof operation, e.g. after switching from normal mode to first powersaving mode. Component 725 includes a component 727 configured tooperate the customer premises device to supply power to a single laserused for upstream communication and keep one or more additional lasersused for upstream communications powered off (during at least some timeperiod) during said first power saving mode of operation. In someexemplary embodiments during the first power saving mode of operationone upstream laser is powered on during a fraction, e.g. ½, ⅓, or ¼, ofthe time in which the customer premises device is in the power savingmode of operation, and 3 additional upstream lasers are powered offduring the full time in which the customer premises device is in thepower saving mode of operation. In some exemplary embodiments during thefirst power saving mode of operation one upstream laser and onecorresponding optical receiver are powered on during a fraction, e.g. ½,⅓, or ¼, of the time in which the customer premises device is in thepower saving mode of operation, and 3 additional upstream lasers with 3additional corresponding optical receivers are powered off during thefull time in which the customer premises device is in the power savingmode of operation.

Assembly of components 700 further includes a component 726 configuredto determine if the switching to the first power saving mode ofoperation is in response to detecting a loss of main power availabilityand to control operation as a function of the determination, and acomponent 728 configured to operate the customer premises device tocommunicate to an optical lien terminal (OLT) that the customer premisesdevice is switching to the first power saving mode of operation, e.g. inresponse to detecting a loss of main power availability.

Assembly of components 700 further includes a component 732 configuredto operate the customer premises device to receive from the OLTscheduling information indicating an amount of time (e.g., a value to beused in count down timer or more advanced scheduling information, thatcan be used to determine a laser and/or optical receiver (OR) power onand off schedule) the customer premises device should maintain its laserused for upstream data communication in a powered off state prior topowering on at least one laser as part of operating in said first powersaving mode of operation, a component 734 configured to operate thecustomer premises device to place the lasers used for upstreamcommunication in the powered off state, a component 736 configured todetermine when said amount of time the customer premises device shouldmaintain its lasers used for upstream data communications in a poweredoff state will be reached, e.g., determine when the count down timerwill expire, a component 738 configured to determine if the amount oftime that the customer premises device is to maintain its lasers, usedfor upstream communication, in the powered off state has been reached,e.g. determine if the countdown timer expired, and to control operationas a function of the determination, a component 740 configured tooperate the customer premises device maintain the lasers, used forupstream data communication, in a powered off time during said amount oftime, e.g. in response to a determination that the count down timer hasnot yet expired, a component 742 configured to determine that the amountof time the customer premises device should maintain its lasers used forupstream communications in the powered off state has been reached, and acomponent 744 configured to operate the customer premises device topower up a first laser, e.g. a primary laser, used for upstreamcommunication in response to determining that the amount of time hasbeen reached, e.g., the count down timer (used for OFF time) expired.Assembly of components 700 further includes a component 746 configuredto operate the customer premises device to send a message to the OLTindicating that the customer premises device is active (e.g., cantransmit data via a first optical transmitter including the first laserin the optical interface and can receive data via a first opticalreceiver in the optical interface).

Assembly of components 700 further includes a component 748 configuredto operate the customer premises device to exchange at least some datawith the OLT, e.g. during a power on time interval. Component 748includes a component 750 configured to operate the customer premisesdevice to transmit data to the OLT using the first laser, a component752 configured to operate the customer premises device to receive datafrom the OLT using a first optical receiver, and a component 754configured to determine that the end of a power on time interval hasbeen reached.

FIG. 8, comprising the combination of FIG. 8A, FIG. 8B and FIG. 8C, is aflowchart 800, of an exemplary method of operating a customer premisesdevice including an optical modem including at least a first laser usedfor upstream communications. In some embodiments, the modem includes asingle laser, e.g., the first laser, for upstream communications. Insome embodiments, the modem includes a plurality of lasers used forupstream communication, said plurality of lasers including the firstlaser. In some embodiments the customer premises device implementing theflowchart 800 is an optical network unit (ONU), e.g., one of ONUs (104,106, . . . , 108) of FIG. 1 or ONU 200 of FIG. 2 or a customer premisesdevice including an ONU including at least one laser used for upstreamcommunications, said customer premises device implemented in accordancewith an exemplary embodiment.

Operation starts in step 802 in which the customer premises device ispowered on and initialized. Operation proceeds from start step 802 tostep 804. In step 804 the customer premises device operates in a normalmode of operation in which the first laser is continuously powered onfor upstream communications. Operation proceeds from step 804 to step806.

In step 806 the customer premises device detects one of: i) a loss inmain power availability or ii) a command to implement a power savingmode of operation, e.g. a first power saving mode of operation.Operation proceeds from step 806 to step 808.

In step 808 the customer premises devices determines to switch to afirst power saving mode of operation. Operation proceeds from step 808to one of: optional step 810, optional step 812 or step 818. In optionalstep 810, the customer premises device communicates to an optical lineterminal (OLT) that the customer premises device is switching to thefirst power saving mode of operation. Operation proceeds from step 810to optional step 812 or to step 818.

In step 812, the customer premises device receives from the OLTscheduling information corresponding to the first power saving mode ofoperation. Step 812 includes step 814 and, in some embodiments includingmultiple upstream lasers, step 816. In step 814 the customer premisesdevice receives from the OLT scheduling information corresponding to thefirst laser including information indicating a first period of time. Instep 816 the customer premises device receives from the OLT schedulinginformation corresponding to more or more additional lasers used forupstream communications, e.g. information indicating when each of theadditional lasers used for upstream communications is to be powered off.Operation proceeds from step 812 to step 818.

In step 818 the customer premises device switches to the first powersaving mode of operation in response to: i) detecting a loss in mainpower availability or ii) detecting a command to implement a powersaving mode of operation, said first power saving mode of operationbeing a mode of operation in which said first laser is powered off forat least a first period of time. In some embodiments, step 818 includesstep 820 or step 822. In step 820 the customer premises device turns offpower to the first laser. In step 822 the customer premises device turnsoff power to each of a plurality of lasers used for upstreamcommunications during the normal mode of operation, said first laserbeing one of said plurality of lasers.

Operation proceeds from step 820 to step 826. Operation proceeds fromstep 822 to steps 826 and 828. Operation also proceeds from step 818,via connecting node A 824, to step 852. In some embodiments, operationproceeds from step 818, via connecting node E 865 to step 866.

Returning to step 826, in step 826, the customer premises device startsa countdown timer to countdown the first period of time. In someembodiments, the first period of time is a period of time determined bya schedule including a first laser inactivity time period. In someembodiments, the first period of time is a period of time specified byan optical line terminal (OLT). Operation proceeds from step 826 to step830. In step 830 the customer premises device checks at to whether ornot the first period of time has expired.

If the determination of step 830 is that the first period of time hasnot yet expired, then operation proceeds from step 830 to step 832. Instep 832 the customer premises devices maintains power off with regardto the first laser. Operation proceeds from step 832 to the input ofstep 830 for another check at a later point time as to whether the firsttime period has expired.

However, if the check of step 830 determines that the first period oftime has expired, then operation proceeds from step 830 to step 834 inwhich the customer premises device determines that the first period oftime has expired. Operation proceeds from step 834 to step 836. In step836 the customer premises device provides power to the first laser, e.g.in response to the determination that the first period of time hasexpired. Operation proceeds from step 836, via connecting node B 838, tostep 840. In step 840 the customer premises device sends, while in thefirst power saving mode of operation, a message to the OLT indicatingthat the customer premises device is active. Operation proceeds fromstep 840 to step 842.

In step 842 the customer premises device exchanges, while in the firstpower saving mode of operation, at least some data with the OLT. Step842 includes steps 844 and 846. In step 844 the customer premises devicetransmits, while in the first power saving mode of operation, data tothe OLT using the first laser. In step 846 the customer premises devicereceives, while in the first power saving mode of operation, data fromthe OLT using a first optical receiver. Operation proceeds from step 842to step 848. In step 848 the customer premises device powers down thefirst laser. Operation proceeds from step 848, via connecting node C 850to the input of step 826.

Returning to step 852, in step 852 the customer premises devicemonitors, while in the first power saving mode of operation, to detecteither of: i) a restoration in main power availability or ii) a commandto implement a normal mode of operation. Step 852, may and sometimesdoes include step 854 in which the customer premises device detects oneof: i) a change in main power availability indicating that main powerhas been restored and is available or ii) a command to implement normalmode of operation. Operation proceeds from step 854 to step 856. In step856 the customer premises device switches to normal mode of operation inresponse to detecting one of: i) a restoration in main poweravailability or ii) a command to implement normal mode of operation.Step 856 includes steps 858 and 860. In step 858 the customer premisesdevice powers on or maintains power to the first laser. In step 860 thecustomer premises device sends a message to the OLT indicating that thecustomer premises device is transitioning to the normal mode ofoperation. Operation proceeds from step 856, via connecting node D 862to step 804, in which the customer premises device is again operated inthe normal mode of operation.

Returning to step 866, in step 866 the customer premises devicemonitors, while in the first power saving mode of operation, to detectan off-hook condition or on-hook condition corresponding to an analogtelephone adaptor (ATA), e.g., an ATA included in (embedded in) orcoupled to the customer premises device. Step 866 may be performed on anongoing basis, e.g. repetitively, while in the first power saving modeof operation. Operation proceeds from step 866 to step 868. If step 868determines that the condition is off-hook, then operation proceeds fromstep 868 to step 870, in which the customer premises device maintainpower to or applies power to the first laser in response to a detectedoff-hook condition. If step 868 determines that the condition ison-hook, then operation proceeds from step 868 to step 872, in which thecustomer premises device powers down the first laser or maintains thefirst laser in a power off state in response to a detected on-hookcondition. In some embodiments, in which step 866 is performed, adetected off-hook condition (while in the first power saving mode ofoperation) results in step 870 being performed and overrides any firstlaser off control in accordance with a schedule, e.g. overrides thefirst period of time.

FIG. 9, comprising the combination of FIG. 9A and FIG. 9B, is a drawingof an exemplary assembly of components 900, comprising Part A 901 andPart B 903, which may be included in a customer premises (CP) device,e.g., a CP device including an optical modem including at least onelaser, e.g., an optical network unit (ONU), in accordance with anexemplary embodiment. Exemplary assembly of components 900 is, e.g.included in customer premises device 200 of FIG. 2, e.g., a ONU, in anyof the customer premises devices (ONU 1 104, ONU 2 106, . . . ONU M 108)of FIG. 1, and/or in an customer premises device, e.g., customerpremises device including an optical modem (such as an ONU) including atleast one laser for upstream communications, implementing the method offlowchart 800 of FIG. 8, implemented in accordance with an exemplaryembodiment.

The components in the assembly of components 900 can, and in someembodiments are, implemented fully in hardware within a processor, e.g.,processor 202, e.g., as individual circuits. The components in theassembly of components 900 can, and in some embodiments are, implementedfully in hardware within the assembly of hardware components 214, e.g.,as individual circuits corresponding to the different components. Inother embodiments some of the components are implemented, e.g., ascircuits, within processor 202 with other components being implemented,e.g., as circuits within assembly of components 214, external to andcoupled to the processor 202. As should be appreciated the level ofintegration of components on the processor and/or with some componentsbeing external to the processor may be one of design choice.Alternatively, rather than being implemented as circuits, all or some ofthe components may be implemented in software and stored in the memory216 of the customer premises device 200, with the components controllingoperation of customer premises device 200 to implement the functionscorresponding to the components when the components are executed by aprocessor e.g., processor 202. In some such embodiments, the assembly ofcomponents 900 is included in the memory 216 as part of assembly ofsoftware components 258. In still other embodiments, various componentsin assembly of components 900 are implemented as a combination ofhardware and software, e.g., with another circuit external to theprocessor providing input to the processor which then under softwarecontrol operates to perform a portion of a component's function.

When implemented in software the components include code, which whenexecuted by a processor, e.g., processor 202, configure the processor toimplement the function corresponding to the component. In embodimentswhere the assembly of components 900 is stored in the memory 216, thememory 215 is a computer program product comprising a computer readablemedium comprising code, e.g., individual code for each component, forcausing at least one computer, e.g., processor 202, to implement thefunctions to which the components correspond.

Completely hardware based or completely software based components may beused. However, it should be appreciated that any combination of softwareand hardware, e.g., circuit implemented components may be used toimplement the functions. As should be appreciated, the componentsillustrated in FIG. 9 control and/or configure the customer premisesdevice 200 or elements therein such as the processor 202, to perform thefunctions of corresponding steps illustrated and/or described in themethod of one or more of the flowcharts, signaling diagrams and/ordescribed with respect to any of the Figures. Thus the assembly ofcomponents 900 includes various components that perform functions ofcorresponding one or more described and/or illustrated steps of anexemplary method, e.g., the method of flowchart 800 of FIG. 8.

Assembly of components 900 includes a component 904 configured tooperate the customer premises device in a normal mode of operation inwhich the first laser is continuously powered on for upstreamcommunications, a component 906 configured to detect one of: i) loss inmain power availability, or ii) a command to implement a power savingsmode of operation, a component 908 configured to determine to switch toa first power saving mode of operation, a component 910 configured tooperate the customer premises device to communicate to an optical lineterminal (OLT) that the customer premises device is switching to thefirst power saving mode of operation, and a component 910 configured tooperate the customer premises device to receive from the OLT schedulinginformation corresponding to the first power saving mode of operation.Component 910 includes a component configured to operate the customerpremises device to receive from the OLT scheduling informationcorresponding to the first laser including a first period of time and acomponent 916 configured to operate the customer premises device toreceive from the OLT scheduling information corresponding to one or moreadditional lased used for upstream communications.

Assembly of components 900 further includes a component 918 configuredto switch to the first power saving mode of operation in response to: i)detecting a loss in main power availability or ii) detecting a commandto implement a power saving mode of operation, said first power savingmode of operation being a mode of operation in which the first laser ispowered off for at least a first period of time. Component 918 includesa component 920 configured to turn off power to the first laser, and acomponent 922 configured to operate the customer premises device to turnoff power to each of a plurality of lasers, used for upstreamcommunications during the normal mode of operation, said first laserbeing one of said plurality of lasers.

Assembly of components 900 further includes a component 926 configuredto start a countdown timer to countdown the first time period, acomponent configured to check if the first period of time has expiredand to control operation as a function of the determination, a component932 configured to maintain power off with regard to the first laserwhile the first countdown timer has not expired, a component 934configured to determine that the first time period has expired, and acomponent 936 configured to operate the customer premises device toprovide power to the first laser, e.g. in response to a determinationthat the first time period has expired.

Assembly of components 900 further includes a component 928 configuredto operate the customer premises device, while in the first power savingmode of operation to control power to one or more additional lasers usedfor upstream communications in accordance with the schedulinginformation corresponding to the one or more additional lasers.

Assembly of components 900 further includes a component 940 configuredto operate the customer premises device to send. while in the firstspower saving mode of operation, a message to the OLT indicating that thecustomer premises device is active, a component 942 configured tooperate the customer premises device to exchange, while in the firstpower saving mode of operation, at least some data with the OLT.Component 942 includes a component 944 configured to operate thecustomer premises device to transmit, while in the first power savingmode of operation, data to the OLT using the first laser and a component946 configured to operate the customer premises device to receive, whilein the first power saving mode of operation, data from the OLT using afirst optical receiver.

Assembly of components 900 further includes a component 952 configuredto monitor, while in the first power saving mode of operation, to detecteither of: i) a restoration in main power availability, or ii) a commandto implement normal mode of operation. Component 952 includes acomponent 954 configured to detect one of: i) a change in main poweravailability indicating that main power has been restored and isavailable, or ii) a command to implement a normal mode of operation.

Assembly of components 900 further includes a component 956 configuredto switch to normal mode of operation in response to detecting one of:i) a restoration in main power availability or ii) a command toimplement normal mode of operation. Component 956 includes a component958 configured to power on or maintain power to the first laser, and acomponent 960 configured to operate the customer premises device to senda message to the OLT indicating that the customer premises device istransitioning to the normal mode. In some embodiments, including aplurality of lasers used for upstream communications in the normal modeof operation, component 958 is configured to power one the full set oflasers used for upstream communications.

Assembly of components 900 further includes a component 966 configuredto monitor, while in the first power saving mode of operation, to detectan off-hook condition or an on-hook condition with regard to an analogtelephone adaptor (ATA), e.g. an ATA included in the customer premisesdevice or an coupled to the customer premises device, a componentconfigured to determine whether an off-hook condition or an on-hookcondition currently exists with regard to the an ATA and to controloperation as a function of the determination, a component 970 configuredto maintain or apply power to the first laser in response to a detectedoff-hook condition, e.g., while in the first power saving mode ofoperation, and a component 972 configured to power down the first laserin response to an on-hook condition, e.g. while in the first powersaving mode of operation.

The numbering used within a particular list of numbered embodimentspertains to that particular list.

First Numbered List of Exemplary Method Embodiments:

Method Embodiment 1 A method of operating a customer premises deviceincluding an optical modem including a plurality of lasers, the methodcomprising: operating (604) in a normal mode of operation in whichmultiple lasers used for upstream communication are powered on;detecting (610) one of a change in main power availability or a commandto implement a mode of operation, said mode of operation being one ofsaid normal mode of operation and a power saving mode of operation; andswitching (622) to a first power saving mode of operation in responseto: i) detecting (614) a command to implement a power saving mode ofoperation or ii) detecting (616) a loss of main power availability.

Method Embodiment 2 The method of Method Embodiment 1, wherein operating(604) in the normal mode of operation includes powering (606) a firstset of lasers and wherein switching (622) to the first power saving modeof operation includes: turning (624) off power to one or more lasers.

Method Embodiment 3 The method of Method Embodiment 2, wherein alllasers which are used for upstream communication are powered on (706)during said normal mode of operation.

Method Embodiment 4 The method of Method Embodiment 3, wherein alldownstream optical receivers are powered and used (608) during saidnormal mode of operation.

Method Embodiment 5 The method of Method Embodiment 2, wherein operatingin the normal mode of operation includes powering (606) a first set oflasers used for upstream communication, the method further comprising:operating (625) in said first power saving mode of operation afterswitching (622) to the first power saving mode of operation, whereinoperating (625) in the first power saving mode of operation including(627) supplying power to a single laser used for upstream communicationand keeping one or more additional lasers used for upstreamcommunication powered off during (at least some time period during) saidfirst power saving mode of operation.

Method Embodiment 6 The method of Method Embodiment 1, wherein saidfirst power saving mode of operation is a maximum power saving mode ofoperation in which at most one upstream laser is operated at any givenpoint in time.

Method Embodiment 7 The method of Method Embodiment 5, wherein saidswitching (622) to a first power saving mode of operation is in responseto detecting a loss of main power availability (616), the method furthercomprising: communicating (628) to an optical line terminal (OLT) thatthe customer premises device is switching to the first power saving modeof operation.

Method Embodiment 8 The method of Method Embodiment 7, furthercomprising: receiving (632) from the OLT scheduling informationindicating an amount of time (e.g., value used in a count down time ormore advanced scheduling information that can be used to determine alaser and/or receiver power on and off schedule) the customer premisesdevice should maintain its lasers used for upstream data communicationin a powered off state prior to powering on at least one laser as partof operating in said first power saving mode of operation; placing (634)the lasers used for upstream communication in the powered off; andmaintaining (640) the lasers used for upstream communication in thepowered off state for said amount of time.

Method Embodiment 9 The method of Method Embodiment 8, furthercomprising: determining (636) when said amount of time the customerpremises device should maintain its lasers used for upstream datacommunication in a powered off state will be reached; and powering (644)up a first laser (e.g., a primary laser) used for upstream communicationin response to determining (642) that the amount of time has beenreached.

Method Embodiment 10 The method of Method Embodiment 9, furthercomprising: sending (646) a message to the OLT indicating that thecustomer premises device is active (e.g., and can transmit and receivedata via the optical interface including the first laser).

Method Embodiment 11 The method of Method Embodiment 10, furthercomprising: transmitting (650) data to the OLT using the first laser;and receiving (652) data from the OLT using a first optical receiver.

Method Embodiment 12 The method of Method Embodiment 10, furthercomprising: exchanging (648) at least some data with the OLT; andplacing (634 repeat iteration) the lasers used for upstreamcommunication in the powered off state; and maintaining (640 repeatiteration) the lasers used for upstream communication in the powered offstate for said amount of time.

Method Embodiment 13 The method of Method Embodiment 12, furthercomprising: detecting (618 or 620) a change in main power availabilityindicating that main power is available or a command to implement thenormal mode of operation; and powering (623) the lasers in the firstgroup of lasers used for upstream communication in response to detectinga change in main power availability indicating that main power isavailable or a command to implement the normal mode of operation.

Second Numbered List of Exemplary Method Embodiments:

Method Embodiment 1 A method of operating a customer premises deviceincluding an optical modem including at least a first laser, the methodcomprising: operating (804) in a normal mode of operation in which thefirst laser is continuously powered on for upstream communications;detecting (806) one of: i) a loss in main power availability or ii) acommand to implement a power saving mode of operation; and switching(818) to a first power saving mode of operation in response to: i)detecting a command to implement a power saving mode of operation or ii)detecting a loss of main power availability, said first power savingmode of operation being a mode of operation in which said first laser ispowered off for at least a first period of time.

Method Embodiment 2 The method of Method Embodiment 1, wherein switching(820) to the first power saving mode of operation includes: turning(820) off power to the first laser.

Method Embodiment 3 The method of Method Embodiment 2, furthercomprising: maintaining (832) first laser used for upstreamcommunication in the powered off state for first period of time.

Method Embodiment 4 The method of Method Embodiment 3, furthercomprising: determining (834) (e.g., using a countdown timer) expirationof said first period of time; and providing (836) power to the firstlaser at the end of said first period of time.

Method Embodiment 5 The method of Method Embodiment 4, wherein saidfirst period of time is a period of time determined by a scheduleincluding a first laser inactivity time period.

Method Embodiment 6 The method of Method Embodiment 4, wherein saidfirst period of time is a period of time specified by an optical lineterminal (OLT).

Method Embodiment 7 The method of Method Embodiment 4, wherein saidcustomer premises device (including the optical modem) includes aplurality of lasers used for upstream communication and wherein saidfirst laser is one of said plurality of lasers used for upstreamcommunication.

Method Embodiment 8 The method of Method Embodiment 7, wherein saidplurality of lasers used for upstream communication are powered onduring said normal mode of operation; and wherein switching (816) to afirst power saving mode of operation includes turning off (822) power toeach of said plurality of lasers used for upstream communication.

Method Embodiment 9 The method of Method Embodiment 7, wherein saidcustomer premises device (including the optical modem) includes aplurality of downstream optical receivers; and wherein said plurality ofdownstream optical receivers are powered and used during said normalmode of operation.

Method Embodiment 10 The method of Method Embodiment 3, wherein saidswitching (816) to a first power saving mode of operation is in responseto detecting a loss of main power availability, the method furthercomprising: communicating (810) to an optical line terminal (OLT) thatthe customer premises device is switching to the first power saving modeof operation.

Method Embodiment 11 The method of Method Embodiment 4, furthercomprising: receiving (814) from the OLT scheduling informationindicating said first period of time.

Method Embodiment 12 The method of Method Embodiment 4, furthercomprising: sending (840), while in the first power saving mode ofoperation, a message to the OLT indicating that the customer premisesdevice is active (e.g., and can transmit and receive data via the firstlaser).

Method Embodiment 13 The method of Method Embodiment 12, furthercomprising: transmitting (844), while in the first power saving mode ofoperation, data to the OLT using the first laser; and receiving (846),while in the first power saving mode of operation, data from the OLTusing a first optical receiver.

Method Embodiment 14 The method of Method Embodiment 12, furthercomprising: exchanging (842), while in the power saving mode ofoperation, at least some data with the OLT; and placing (848) the firstlaser in the powered off

Method Embodiment 15 The method of Method Embodiment 2, furthercomprising: detecting (854) one of: i) a change in main poweravailability indicating that main power has been restored and isavailable or ii) a command to implement the normal mode of operation;and switching (856) to normal mode of operation in response to:detecting (854) one of: i) a change in main power availabilityindicating that main power has been restored and is available or ii) acommand to implement the normal mode of operation.

Method Embodiment 16 The method of Method Embodiment 15, whereinswitching (856) to normal mode of operation includes: powering (858) onor maintaining power to the first laser; and sending (860) a message tothe OLT indicating that the customer premises device is switching tonormal mode.

Method Embodiment 17 The method of Method Embodiment 2, furthercomprising: monitoring (866), while in the first power saving mode ofoperation, to detect one of: an on-hook condition or an off hookcondition corresponding to an analog-telephone-adaptor (ATA); inresponse to detecting an off-hook condition, maintain or apply power(870) to the first laser; and in response to detecting an on-hookcondition, power down (872) the first laser.

First Numbered List of Exemplary Apparatus Embodiments:

Apparatus Embodiment 1 A customer premises device (200 or 104 or 106 or108) (including an optical modem including a plurality of lasers), thecustomer premises device (200) comprising: a plurality of lasers (219,223, 227, 231) for upstream communication; a plurality of opticalreceivers (220, 224, 228, 232) for downstream communication; a powermonitoring circuit (246) configured to monitor main power availability;and a processor (202) configured to: operate (604) the customer premisesdevice (202) in a normal mode of operation in which multiple lasers(219, 223, 227, 231) used for upstream communication are powered on;detect (610) one of a change in main power availability or a command toimplement a mode of operation, said mode of operation being one of saidnormal mode of operation and a power saving mode of operation; andswitch (622) to a first power saving mode of operation in response to:i) detecting (614) a command to implement a power saving mode ofoperation or ii) detecting (616) a loss of main power availability.

Apparatus Embodiment 2 The customer premises device (200) of ApparatusEmbodiment 1, wherein said processor (202) is configured to power (606)a first set of lasers (219, 223, 227, 231) as part of being configuredto operate (604) in the normal mode of operation; and wherein saidprocessor (202) is configured to turn (624) off power to one or morelasers (219, 223, 227, 231), as part of being configured to switching(622) to the first power saving mode of operation.

Apparatus Embodiment 3 The customer premises device (200) of ApparatusEmbodiment 2, wherein all lasers (219, 223, 227, 231) which are used forupstream communication are powered on (706) during said normal mode ofoperation.

Apparatus Embodiment 4 The customer premises device (200) of ApparatusEmbodiment 3, wherein all downstream optical receivers (220, 224, 228,232) are powered and used (608) during said normal mode of operation.

Apparatus Embodiment 5 The customer premises device (200) of ApparatusEmbodiment 2, wherein said processor (202) is configured to: power (606)a first set of lasers (219, 223, 227, 231) used for upstreamcommunication, as part of being configured to operate in the normal modeof operation; and operate (625) in said first power saving mode ofoperation after switching (622) to the first power saving mode ofoperation, wherein operating (625) in the first power saving mode ofoperation including (627) supplying power to a single laser (219) usedfor upstream communication and keeping one or more additional lasers(223, 227, 231) used for upstream communication powered off during (atleast some time period during) said first power saving mode ofoperation.

Apparatus Embodiment 6 The customer premises device (200) of ApparatusEmbodiment 1, wherein said first power saving mode of operation is amaximum power saving mode of operation in which at most one upstreamlaser (219) is operated at any given point in time.

Apparatus Embodiment 7 The customer premises device (200) of ApparatusEmbodiment 5, wherein said switching (622) to a first power saving modeof operation is in response to detecting a loss of main poweravailability (616); and wherein said processor (202) is furtherconfigured to: operate the customer premises device (200) to communicate(628) to an optical line terminal (OLT) (102) that the customer premisesdevice (200) is switching to the first power saving mode of operation.

Apparatus Embodiment 8 The customer premises device (200) of ApparatusEmbodiment 7, wherein said processor (202) is further configured to:operate the customer premises device (202) to receive (632) (e.g., via afirst optical receiver (220)) from the OLT (102) scheduling informationindicating an amount of time (e.g., value used in a count down time ormore advanced scheduling information that can be used to determine alaser and/or receiver power on and off schedule) the customer premisesdevice (200) should maintain its lasers (219, 223, 227, 231) used forupstream data communication in a powered off state prior to powering onat least one laser (219) as part of operating in said first power savingmode of operation; operate the customer premises device (200) to place(634) the lasers (219, 223, 227, 231) used for upstream communication inthe powered off; and operate the customer premises device (200) tomaintain (640) the lasers (219, 223, 227, 231) used for upstreamcommunication in the powered off state for said amount of time.

Apparatus Embodiment 9 The customer premises (200) of ApparatusEmbodiment 8, wherein said processor (202) is further configured to:determine (636) when said amount of time the customer premises device(200) should maintain its lasers (219, 223, 227, 231) used for upstreamdata communication in a powered off state will be reached; and operatethe customer premises device (200) to power (644) up a first laser (219)(e.g., a primary laser) used for upstream communication in response todetermining (642) that the amount of time has been reached.

Apparatus Embodiment 10 The customer premises device (200) of ApparatusEmbodiment 9, wherein said processor (202) is further configured to:operate the customer premises device (200) to send (646) a message tothe OLT (102) indicating that the customer premises device (200) isactive (e.g., and can transmit and receive data via the opticalinterface including the first laser).

Apparatus Embodiment 11 The customer premises device (200) of ApparatusEmbodiment 10, wherein said processor (202) is further configured to:operate the customer premises device (200) to transmit (650) data to theOLT (102) using the first laser (219); and operate the customer premisesdevice (200) to receive (652) data from the OLT (102) using a firstoptical receiver (220).

Apparatus Embodiment 12 The customer premises device (200) of ApparatusEmbodiment 10, wherein said processor (202) is further configured to:operate the customer premises device (200) to exchange (648) at leastsome data with the OLT (102); and operate the customer premises device(200) to place (634 repeat iteration) the lasers (219, 223, 227, 231)used for upstream communication in the powered off state; and operatethe customer premises device (200) to maintain (640 repeat iteration)the lasers (219, 223, 227, 231) used for upstream communication in thepowered off state for said amount of time.

Apparatus Embodiment 13 The customer premises device (200) of ApparatusEmbodiment 12, wherein said processor (202) is further configured to:detect (618 or 620) a change in main power availability indicating thatmain power is available or a command to implement the normal mode ofoperation; and operate the customer premises device (202) to power (623)the lasers (219, 223, 227, 229) in the first group of lasers used forupstream communication in response to detecting a change in main poweravailability indicating that main power is available or a command toimplement the normal mode of operation.

Second Numbered List of Exemplary Apparatus Embodiments:

Apparatus Embodiment 1 A customer premises device (200 or 104 or 106 or108) (including an optical modem including at least a first laser), thecustomer premises device (200) comprising: a first laser (219) forupstream communication; a first optical receiver (220) for downstreamcommunication; a power monitoring circuit (246) configured to monitormain power availability; and a processor (202) configured to: operate(804) the customer premises device in a normal mode of operation inwhich the first laser is continuously powered on for upstreamcommunications; detect (806) one of: i) a loss in main poweravailability or ii) a command to implement a power saving mode ofoperation; and switch (818) to a first power saving mode of operation inresponse to: i) detecting a command to implement a power saving mode ofoperation or ii) detecting a loss of main power availability, said firstpower saving mode of operation being a mode of operation in which saidfirst laser is powered off for at least a first period of time.

Apparatus Embodiment 2 The customer premises device of ApparatusEmbodiment 1, wherein said processor is configured to: turn (820) offpower to the first laser, as part of being configured to switch (820) tothe first power saving mode of operation.

Apparatus Embodiment 3 The customer premises device of ApparatusEmbodiment 2, wherein said processor is configured to: maintain (832)first laser used for upstream communication in the powered off state forfirst period of time.

Apparatus Embodiment 4 The customer premises device of ApparatusEmbodiment 3, wherein said processor is further configured to: determine(834) (e.g., using a countdown timer) expiration of said first period oftime; and provide (836) power to the first laser at the end of saidfirst period of time.

Apparatus Embodiment 5 The customer premises device of ApparatusEmbodiment 4, wherein said first period of time is a period of timedetermined by a schedule including a first laser inactivity time period.

Apparatus Embodiment 6 The customer premises device of ApparatusEmbodiment 4, wherein said first period of time is a period of timespecified by an optical line terminal (OLT).

Apparatus Embodiment 7 The customer premises device of ApparatusEmbodiment 4, further comprising: one or more additional lasers (223,227, 231) used for upstream communications, wherein said first laser(219) and said one or more additional lasers (223, 227, 231) used forupstream communications, are a plurality of lasers (219, 223, 227, 231)used for upstream communications.

Apparatus Embodiment 8 The customer premises device of ApparatusEmbodiment 7, wherein said processor is configured to: powered on saidplurality of lasers used for upstream communication (219, 223, 227, 231)during said normal mode of operation; and wherein said processor isconfigured to turn off (822) power to each of said plurality of lasers(219, 223, 227, 231) used for upstream communication, as part of beingconfigured to switch (816) to a first power saving mode of operation.

Apparatus Embodiment 9 The customer premises device of ApparatusEmbodiment 7, further comprising: a plurality of downstream opticalreceivers (220, 224, 228, 232); and wherein said processor is configuredto power on and use said plurality of downstream optical receiversduring said normal mode of operation.

Apparatus Embodiment 10 The customer premises device of ApparatusEmbodiment 3, wherein said processor is configured to: operate thecustomer premises device to communicate (810) to an optical lineterminal (OLT) that the customer premises device is switching to thefirst power saving mode of operation.

Apparatus Embodiment 11 The customer premises device of ApparatusEmbodiment 4, wherein said processor is further configured to: operatethe customer premises device to receive (814) from the OLT schedulinginformation indicating said first period of time.

Apparatus Embodiment 12 The customer premises device of ApparatusEmbodiment 4, wherein said processor is further configured to: operatethe customer premises device to send (840), while in the first powersaving mode of operation, a message to the OLT indicating that thecustomer premises device is active (e.g., and can transmit and receivedata via the first laser).

Apparatus Embodiment 13 The customer premises device of ApparatusEmbodiment 12, wherein said processor is configured to: operate thecustomer premises device to transmit (844), while in the first powersaving mode of operation, data to the OLT using the first laser (219);and operate the customer premises device to receive (846), while in thefirst power saving mode of operation, data from the OLT using a firstoptical receiver (220).

Apparatus Embodiment 14 The customer premises device of ApparatusEmbodiment 12, wherein said processor is configured to: operate thecustomer premises device to exchange (842), while in the power savingmode of operation, at least some data with the OLT; and placing (848)the first laser (219) in the powered off state.

Apparatus Embodiment 15 The customer premises device of ApparatusEmbodiment 2, wherein said processor is further configured to: detect(854) one of: i) a change in main power availability indicating thatmain power has been restored and is available or ii) a command toimplement the normal mode of operation; and switch (856) to normal modeof operation in response to: detecting (854) one of: i) a change in mainpower availability indicating that main power has been restored and isavailable or ii) a command to implement the normal mode of operation.

Apparatus Embodiment 16 The customer premises device of ApparatusEmbodiment 15, wherein said processor is configured to: powering (858)on or maintaining power to the first laser; and operate the customerpremises device to send (860) a message to the OLT indicating that thecustomer premises device is switching to normal mode, as part of beingconfigured to switch (856) to normal mode of operation.

Apparatus Embodiment 17 The customer premises device of ApparatusEmbodiment 2, wherein said processor is further configured to: monitor(866), while in the first power saving mode of operation, to detect oneof a on-hook condition or an off hook condition corresponding to ananalog-telephone-adaptor (ATA) (299); in response to detecting anoff-hook condition, maintain or apply power (870) to the first laser(219); and in response to detecting an on-hook condition, power down(872) the first laser (219).

First Numbered List of Exemplary

Non-Transitory Computer Readable Medium Embodiments:

Non-Transitory Computer Readable Medium Embodiment 1 A non-transitorycomputer readable medium (216) including computer executableinstructions which when executed by a processor (202) of a customerpremises device (200) (e.g., a device including an optical modemincluding a plurality of lasers (219, 223, 227, 231) cause the customerpremises device (200) to perform the steps of: operating (604) in anormal mode of operation in which multiple lasers used for upstreamcommunication are powered on; detecting (610) one of a change in mainpower availability or a command to implement a mode of operation, saidmode of operation being one of said normal mode of operation and a powersaving mode of operation; and switching (622) to a first power savingmode of operation in response to: i) detecting (614) a command toimplement a power saving mode of operation or ii) detecting (616) a lossof main power availability.

Second Numbered List of Exemplary

Non-Transitory Computer Readable Medium Embodiments:

Non-Transitory Computer Readable Medium Embodiment 1 A non-transitorycomputer readable medium (216) including computer executableinstructions which when executed by a processor (202) of a customerpremises device (200) (e.g., a device including an optical modemincluding at least one laser (219)) cause the customer premises device(200) to perform the steps of: operating (804) in a normal mode ofoperation in which the first laser is continuously powered on forupstream communications; detecting (806) one of: i) a loss in main poweravailability or ii) a command to implement a power saving mode ofoperation; and switching (818) to a first power saving mode of operationin response to: i) detecting a command to implement a power saving modeof operation or ii) detecting a loss of main power availability, saidfirst power saving mode of operation being a mode of operation in whichsaid first laser is powered off for at least a first period of time.

While a laser may be, and sometimes is, powered down during at leastsome period of time during power save mode of operation, the methods andapparatus still allow for device availability in at least someembodiments where detection of an off-hook condition of a telephone orother device at a customer premise is detected and trigger powering upof at least one laser and/or resumption of normal mode operation. In onesuch embodiment once an on-hook condition of the device, e.g., phone,which was detected going off hook during power saving mode operation,and thus triggering powering of the laser, is detected as going on hookpower saving mode is resumed and the laser is powered off, e.g., for aperiod of time and/or according to a schedule.

By supporting power saving mode operation, the methods and apparatus ofthe invention allow for use of a backup battery which can be of areasonable size for a residential application while still allowing for24 hour availability for voice calls during power outages and/oremergencies. The methods and apparatus can also be used to facilitatereaching of voluntary small network equipment power consumption targetsand/or government mandated power consumption requirements forresidential device in the event they are implemented or already exist.

Significantly, while an optical network unit implemented in accordancewith the invention may enter a power saving mode of operation, the ONUcan remain registered with a network device such as an OLT in at leastsome embodiments. After an initial registration with an OLT, e.g., afterpower up, the ONU is able to support voice calls. In one such embodimentthe OLT keeps the ONU registered even though it may temporarily cease tocommunicate with the ONU due to ONU power saving mode operation anddepowering of the ONU's laser or lasers and/or optical receivers for aperiod of time. In such embodiments on powering up its laser or lasersand/or optical receiver(s), the ONU can proceed with communicating withthe OLT and proceeding with a voice call without having to re-register.This allows for rapid voice call support even when an ONU switches frompower saving to powered operation in response to a device such as aphone going off hook allowing for rapid placement of calls, e.g., inemergencies, since re-registration can be avoided as compared toembodiments where an ONU needs to re-register after ceasingcommunication with an OLT, e.g., due to a laser or receiver beingpowered off.

In some embodiments, the processor or processors, e.g., CPUs, of one ormore devices, are configured to control the devices, e.g., optical lineterminal or customer premises device including an optical modem, inwhich they are located to perform the steps of the methods described asbeing performed by the communications nodes, e.g., controllers. Theconfiguration of the processor may be achieved by using one or morecomponents, e.g., software components, to control processorconfiguration and/or by including hardware in the processor, e.g.,hardware components, to perform the recited steps and/or controlprocessor configuration. The components in devices may be implementedusing software and/or hardware.

Some embodiments are directed to a computer program product comprising acomputer-readable medium, e.g., a non-transitory computer-readablemedium, comprising code for causing a computer, or multiple computers,to implement various functions, steps, acts and/or operations, e.g. oneor more steps described above.

Depending on the embodiment, the computer program product can, andsometimes does, include different code for each step to be performed.Thus, the computer program product may, and sometimes does, include codefor each individual step of a method, e.g., a method of controlling acontroller or node. The code may be in the form of machine, e.g.,computer, executable instructions stored on a computer-readable medium,e.g., a non-transitory computer-readable medium, such as a RAM (RandomAccess Memory), ROM (Read Only Memory) or other type of storage device.In addition to being directed to a computer program product, someembodiments are directed to a processor configured to implement one ormore of the various functions, steps, acts and/or operations of one ormore methods described above. Accordingly, some embodiments are directedto a processor, e.g., CPU, configured to implement some or all of thesteps of the methods described herein. The processor may be for use in,e.g., a communications device such as an optical line terminal oroptical modem. In some embodiments components are implemented ashardware devices in such embodiments the components are hardwarecomponents. In other embodiments components may be implemented assoftware, e.g., a set of processor or computer executable instructions.Depending on the embodiment the components may be all hardwarecomponents, all software components, a combination of hardware and/orsoftware or in some embodiments some components are hardware componentswhile other components are software components.

Numerous additional variations on the methods and apparatus of thevarious embodiments described above will be apparent to those skilled inthe art in view of the above description. Such variations are to beconsidered within the scope. Numerous additional embodiments, within thescope of the present invention, will be apparent to those of ordinaryskill in the art in view of the above description and the claims whichfollow. Such variations are to be considered within the scope of theinvention.

What is claimed is:
 1. A method of operating a customer premises deviceincluding an optical modem including at least a first laser, the methodcomprising: operating in a normal mode of operation in which the firstlaser is continuously powered on for upstream communications; detectingone of: i) a loss in main power availability or ii) a command toimplement a power saving mode of operation; switching to a first powersaving mode of operation in response to: i) detecting a command toimplement a power saving mode of operation or ii) detecting a loss ofmain power availability, said first power saving mode of operation beinga mode of operation in which said first laser is powered off for atleast a first period of time, wherein switching to the first powersaving mode of operation includes: turning off power to the first laser;monitoring, while in the first power saving mode of operation, to detectone of an on-hook condition or an off hook condition corresponding to ananalog-telephone-adaptor (ATA); in response to detecting an off-hookcondition, maintaining or applying power to the first laser; and inresponse to detecting an on-hook condition, powering down the firstlaser.
 2. The method of claim 1, further comprising: maintaining firstlaser used for upstream communication in the powered off state for firstperiod of time.
 3. The method of claim 2, further comprising:determining expiration of said first period of time; and providing powerto the first laser at the end of said first period of time.
 4. Themethod of claim 3, wherein said customer premises device includes aplurality of lasers used for upstream communication and wherein saidfirst laser is one of said plurality of lasers used for upstreamcommunication.
 5. The method of claim 4, wherein said plurality oflasers used for upstream communication are powered on during said normalmode of operation; and wherein switching to a first power saving mode ofoperation includes turning off power to each of said plurality of lasersused for upstream communication.
 6. The method of claim 3, furthercomprising: receiving from the OLT scheduling information indicatingsaid first period of time.
 7. The method of claim 3, further comprising:sending, while in the first power saving mode of operation, a message tothe OLT indicating that the customer premises device is active.
 8. Themethod of claim 7, further comprising: transmitting, while in the firstpower saving mode of operation, data to the OLT using the first laser;and receiving, while in the first power saving mode of operation, datafrom the OLT using a first optical receiver.
 9. The method of claim 7,further comprising: exchanging, while in the power saving mode ofoperation, at least some data with the OLT; and placing the first laserin the powered off state.
 10. The method of claim 2, wherein saidswitching to a first power saving mode of operation is in response todetecting a loss of main power availability, the method furthercomprising: communicating to an optical line terminal (OLT) that thecustomer premises device is switching to the first power saving mode ofoperation.
 11. The method of claim 1, further comprising: detecting oneof: i) a change in main power availability indicating that main powerhas been restored and is available or ii) a command to implement thenormal mode of operation; and switching to normal mode of operation inresponse to: detecting one of: i) a change in main power availabilityindicating that main power has been restored and is available or ii) acommand to implement the normal mode of operation.
 12. A customerpremises device, the customer premises device comprising: a first laserfor upstream communication; a first optical receiver for downstreamcommunication; a power monitoring circuit configured to monitor mainpower availability; and a processor configured to: operate the customerpremises device in a normal mode of operation in which the first laseris continuously powered on for upstream communications; detect one of:i) a loss in main power availability or ii) a command to implement apower saving mode of operation; and switch to a first power saving modeof operation in response to: i) detecting a command to implement a powersaving mode of operation or ii) detecting a loss of main poweravailability, said first power saving mode of operation being a mode ofoperation in which said first laser is powered off for at least a firstperiod of time, wherein said switch to the first power saving mode ofoperation includes turning off power to the first laser; monitor, whilein the first power saving mode of operation, to detect one of an on-hookcondition or an off hook condition corresponding to ananalog-telephone-adaptor (ATA); in response to detecting an off-hookcondition, maintain or apply power to the first laser; and in responseto detecting an on-hook condition, power down the first laser.
 13. Thecustomer premises device of claim 12, wherein said processor isconfigured to: maintain the first laser used for upstream communicationin a powered off state for the first period of time.
 14. The customerpremises device of claim 13, wherein said processor is furtherconfigured to: determine expiration of said first period of time; andprovide power to the first laser at the end of said first period oftime.
 15. The customer premises device of claim 14, further comprising:one or more additional lasers used for upstream communications, whereinsaid first laser and said one or more additional lasers used forupstream communications are a plurality of lasers used for upstreamcommunications.
 16. The customer premises device of claim 15, whereinsaid processor is configured to: powered on said plurality of lasersused for upstream communications during said normal mode of operation;and wherein said processor is configured to turn off power to each ofsaid plurality of lasers used for upstream communications, as part ofbeing configured to switch to a first power saving mode of operation.17. A non-transitory computer readable medium including computerexecutable instructions which when executed by a processor of a customerpremises device including an optical modem including at least a firstlaser cause the customer premises device to perform the steps of:operating in a normal mode of operation in which the first laser iscontinuously powered on for upstream communications; detecting one of:i) a loss in main power availability or ii) a command to implement apower saving mode of operation; switching to a first power saving modeof operation in response to: i) detecting a command to implement a powersaving mode of operation or ii) detecting a loss of main poweravailability, said first power saving mode of operation being a mode ofoperation in which said first laser is powered off for at least a firstperiod of time, wherein switching to the first power saving mode ofoperation includes: turning off power to the first laser; monitoring,while in the first power saving mode of operation, to detect one of aon-hook condition or an off hook condition corresponding to ananalog-telephone-adaptor (ATA); in response to detecting an off-hookcondition, maintain or apply power to the first laser; and in responseto detecting an on-hook condition, power down the first laser.